The present invention relates to the field of concrete blocksand, in particular, to a process for splitting dual blocks and an apparatus used in the process.
Cast concrete blocks are well known in the construction industry. They have a wide range of uses including constructing retaining and other walls, paving stones, edge restraints, base material, interlocking blocks, masonry products, and barriers. The interlocking blocks are advantageous for use since mortar is not needed to hold the blocks in place and strengthen the wall. The blocks are preferably cast as a dual block so that each cast block can be split into two individual blocks. This process increases the efficiency of the manufacturing process and gives an aesthetically desirable irregular or natural looking surface to the block face.
The manufacturing process includes at least one manufacturing step to cast the dual block and a separate manufacturing step to split the dual block into its individual blocks. U.S. Pat. No. 5,017,049 issuing May 21, 1991 to Sievert describes a masonry block and its construction. Sievert outlines a process where the block is formed in a mould, the block is cured, and then the block is split into its two component blocks The block is split using a manual chisel and hammer or with a machine designed for this purpose. U.S. Pat. No. 5,598,679 issuing Feb. 4, 1997 to Orton et al. describes a process for splitting a cast concrete block into three blocks. Again, the block is formed in a mould, cured and then split. The cured block is split into its component blocks by advancing splitting knives along the cutting grooves.
These known processes require a separate step in the manufacturing process, specialized machinery and result in increased handling of the blocks. This requirement results in additional costs to the manufacturer. There therefore is a need for a process for casting concrete blocks were dual blocks can be split into individual blocks without the need for additional machinery and an additional manufacturing step. There also is a need for a process for casting concrete blocks which is more economical and which reduces the handling of the blocks.
The present invention provides a process for the manufacture of dual blocks were the dual blocks are split into individual blocks before the block is cured.
The present invention also provides an economical process for the manufacture of concrete dual blocks which are split into separate units during the manufacturing process before curing without the need for an additional manufacturing step.
The present invention also provides for an apparatus used in the process of manufacturing of cast concrete blocks.
There therefore is provided a method for the casting of a concrete dual block comprising the steps of: compressing wet concrete into a block shape having a top surface and a bottom surface, each of said surfaces having a pair of opposite side edges, at least the bottom surface having a separation line extending along its width intermediate said side edges and said bottom surface being generally curved so that at least one of said side edges is at an elevation above said separation line; and allowing the compressed mixture to settle on a substantially flat surface; the difference between the elevation of said separation line and said at least one of said side edges being selected to force the block to split substantially along the separation line upon settling of the block.
In a further aspect of the present invention, there is provided a moulded dual block having a length L and a width W and comprising an upper face, lower face, opposing end faces having upper and lower edges, and a separation line extending along the width on said upper and lower faces intermediate said end faces of said dual block, each of said upper and lower faces comprising two surfaces extending from said separation line towards said end faces along said length.
In a further aspect of the present invention, there is also provided a mould for forming a dual block comprising a bottom plate having an upper face having opposing side edges, a separation line intermediate said side edges, and at least one of said side edges having an elevation above said separation line.
In a still further aspect of the present invention, there is provided an apparatus for forming a moulded dual block comprising: a mould including a bottom plate having an upper face having opposing side edges, an upper plate having a lower face having opposing side edges, a separation line intermediate said side edges of at least one of said upper face of said bottom plate and said lower face of said upper plate, and at least one of said side edges having an elevation above said separation line, said elevation of said side edges selected to force said dual block to split along said separation line when the dual block is allowed to settle on a flat surface; means for filling the mould with wet concrete; and means for releasing the dual block from the mould.